No unfortunately not.
Seems the whole thing is even more tricky. Apparently the skin is applied before plugins are loaded on login, so after login most assets are not skinned properly. Even if the skin would apply after plugin loading, reloading a plugin would screw it again.
Some assets however are always skinned, so I think Turbine only marked a few IDs to check for a skin overriding them, while activating a skin for some reason checks all Lua controls and replaces images.
For example 0x410001c9 (default "left" button in dressing room and when splitting stacks) does always get skinned properly, 0x410001ca however only shows properly when a control already uses it when a skin gets activated.
I'm not really sure why those IDs behave differently...do the skinnable ArtAssetID in the SkinDefinition.xml have a 1:1 relation to the numeric asset ID we can use in Lua? Or are several ArtAssetID refering to the same internal image by default?
Somehow seems like an unfinished attempt to make ("custom") Lua controls support skins...
Too bad Turbine.UI.Lotro lacks several vital elemets to do a proper configuration panel
